Ceramic Tibial Plateaus (Osteo)

Accession Number: 2025.JAC.297.1-2

Alternative Name:

Primary Materials: Ceramic

Markings:

Dimensions (cm): Height = .5, Width = 4.5, Length = 3.2

These artifacts are ceramic tibial plateaus that were designed to be used as part of a partial knee replacement developed at the Toronto General Hospital during the 1970s

These items are likely prototypes of a design that did not make it to market.

All items are in very good cosmetic condition and appear to be unused. Both have subtle grey discoloration around their edges.

Associated Instruments:

Manufacturer: Likely Osteo AG, Selzach, Switzerland.

Date of Manufacture: c. 1979

This and other items related to the development of a partial knee replacement based on a MacIntosh plateau and a plastic femoral component were likely gathered by Dr. Robert W. Jackson during his time on staff at the Division of Orthopedic Surgery

The Robert W. Jackson Arthroscopy Collection was acquired by the University of Toronto from Dr. Jackson’s family on November 12th, 2020.

Robert W. Jackson, Frederick P. Dewar, David L. MacIntosh, John P. Kostuik, and Robin Black. US4034418A: Artificial knee joint. US Patent. Awarded July 12, 1977.

Günther Heimke, Stefan Leyen, and Gerd Willmann. “Knee Arthoplasty: Recently Developed Ceramics Offer New Solutions.” Biomaterials 23, no. 7 (2002). 

The MacIntosh hemiarthroplasty (tibial plateau) was developed at the Toronto General Hospital (TGH) beginning in 1954. It is named for its inventor, orthopedic surgeon David L. MacIntosh (1914 – 2013). This was a platform that replaced the bearing surface of a tibial condyle. Though various materials were tried, after 1965, these were made exclusively of Vitallium. A detailed history of that development can be found in these catalogued examples. 

At some point, possibly in the late 1960s, efforts began to create a femoral implant to match the tibial plateau in order to create a complete partial knee replacement. Little is known so far about the specifics of this effort. However, the Jackson Collection contains several intriguing prototype artifacts. The best source is a 1977 patent (US patent 4,034,418), led by Robert W. Jackson and assigned to the University of Toronto, that describes a mature version of this arrangement.

At some point, it was decided to experiment with a ceramic tibial surface rather than a metal one. When or why these experiments began is not known, though artifact 2025.JAC.296.1-4 shows that the Swiss manufacturer Osteo AG delivered two complete examples in April of 1979. Whether this indicates that Osteo fabricated other examples of plastic femoral components from this project is uncertain, though it seems likely.

Experiments with ceramic tibial plateaus based on the MacIntosh model had been undertaken beginning in the early 1970s at the Rudolf-Elle-Hospital in Eisemberg, Germany and the Orthopedic Clinic of the University of Jena, Germany (see Heimke, Leyen, and Willmann 2002, 1542). Whether this work had any relationship to the collaboration between TGH and Osteo is unclear. 

An Unconventional Arrangement

With the benefit of decades of experience, medical manufacturers have settled on a conventional arrangement for an artificial knee joint. Whether partial or complete, this consists of a metal tibial component that serves as a platform for a plastic (high-density polyethylene HDPE) tibial liner that forms the tibial bearing surface. The metal femoral implant component bears upon this lower plastic liner. 

The developmental efforts towards a partial knee replacement that emerged from the MacIntosh hemiarthroplasty reversed this arrangement, with a plastic (likely HDPE) femoral implant on top and a metal or ceramic tibial component on the bottom. This arrangement was tested and likely proved unworkable. This technology did not make it to market, though, as this artifact shows, prototypes were provided by a major manufacturer.